Two or more cables, such as telecommunications cables, must often be spliced together to extend or tap into a cable. The formation of a splice involves removal of the outer jacket and other layers of the cable to expose the individual conductors or optical fibers which are then individually connected to the conductors or fibers of another cable or cables. After the splice is formed, it must be protected from water and other vapors to prevent corrosion or a short circuit. For this purpose, the splice area is often enclosed in a splice case that is formed from two trough-like shell members having end plates through which the cables pass. The effectiveness of the splice case depends significantly on the mechanism used to seal the seam formed at the interface where the two shells meet.
In one known sealing arrangement, the two shell members each include integrally formed flanges that contact one another to form a seam. The seam is sealed by a series of bolts that pass through the flanges. Closure systems of this type are shown, for example, in a 1990 product catalog published by PSI Telecommunications Incorporated, entitled "2-Type Closure System". One problem with this arrangement is that the force exerted by the bolts is not uniform across the seam. Rather, the force is at a maximum in the vicinity of the bolts and is reduced at locations between the bolts. As a result, the bolts must be closely spaced along the seam to ensure an adequate seal, thus increasing the cost of the splice case and the installation time associated with its use
In other sealing arrangements, the flanges receive clamping elements that extend along the seam. The clamping elements apply pressure to the flanges across their entire length. As disclosed in U.S. Pat. Nos. 5,048,916 (Caron) and 4,715,740 (Pichler), for example, the flanges and clamps are wedge-shaped so that the clamps can be more easily slipped over the flanges. While this arrangement can provide a relatively uniform pressure distribution across the seam, the pressure distribution is very susceptible to any irregularities in the wedges arising from the moulding process. Moreover, clamping mechanisms of this type requires the clamp to travel a significant distance over the flange. During this assembly process, the sealing force often becomes so great that it cannot be completed without the use of a tool. Indeed, clamps of this type are often hammered into place when they are installed in the field. This process can damage copper wire splices and the seal integrity for the closure, and is unacceptable for fiber optics splices. Moreover, because of the significant travel distance that is required to engage the flange, the size of the work area in which the closure is assembled and disassembled will also need to be correspondingly large. This is frequently problematic in the field, since the splice case is often installed in confined spaces such as a manholes or hand holes where there is very little space beyond that occupied by the splice case itself. Accordingly, there is a need in the art for a sealing arrangement for a closure, such as a splice case, in which uniform pressure is applied across the seam, which is easily engaged and disengaged from the closure (e.g., by hand), and which requires a minimum amount of working space for the clamp to be permanently mounted to the closure.
Another problem with prior art closure systems is that the closure mechanism is not permanently attached to the closure housing. Indeed, the length of many prior art closure ramps makes permanent attachment of the closure to the housing impractical. As a result, when access to the closure is desired, the clamps, bolts, or other closure devices must be removed from the splice enclosure until the work is completed. Since splice closures are frequently installed on elevated utility lines, the removed parts are easily dropped or lost, thus adding to the time and cost of work on the splice closure and often resulting in the closure system being reassembled improperly and without all of the original parts. There is thus a need in the art for a closure system in which the sealing or clamping mechanism can be permanently attached to the closure housing.
These and other needs are met by the present invention, as hereinafter described.